Reliable Insights

The most common way to learn about the expiry date of your website's SSL certificate is after it has expired. The blackbox exporter combined with Prometheus can let you know well in advance, letting you renew your certificate before users complain.

The next step is to hook this in to Prometheus, and create an alert. We'll usually want to probe multiple endpoints coming from service discovery with the same blackbox exporter, so we use relabelling to convert the target addresses to URL parameters: